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Published byEustacia Wilcox Modified over 9 years ago
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Innovations in Log Transportation John Sessions Oregon State University
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Problem Definition Rising fuel costs and pollution control costs Increasing road user costs Fewer available trucks
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Opportunities Increase load size Reduce road use costs Improve truck scheduling
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Increase Load Size Load size is a function of - tire width - tire width - weight per axle - weight per axle - number of axles - number of axles - axle spacing - axle spacing Add additional axles (lift axles, trailers) Reduce log weight
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Maximizing Load Max w i Max w i w i < b i w i < b i w dk < r k w dk < r k w i > 0 w i > 0 w i = loading on axle i w i = loading on axle i b i = upper limit for axle i b i = upper limit for axle i d = axles in axle group k d = axles in axle group k r k = upper limit for group k r k = upper limit for group k
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Reduce Log Weight Reduce Bark Mechanized delimbing Reduce Water Girdling Girdling Stockpiling Stockpiling
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Girdling Girdle sapwood of standing tree one to two weeks before felling and let transpiration reduce water content Girdle sapwood of standing tree one to two weeks before felling and let transpiration reduce water content Fell tree and leave top attached for several weeks Fell tree and leave top attached for several weeks
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Researchable Questions How long does transpiration continue after full, partial girdling? If transpiration continues, what is the rate of water use Variables: species, temperature, wind Example: mature tree during summer uses 20+ gallons (160+ lbs) per day
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Benefits and Costs Benefits - Loading - Loading - Hauling - Drying Costs - Girdling - Girdling - Sawing productivity (?) - Sawing productivity (?) - Wood quality - Wood quality
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Reduce Road User Costs Road User Costs On Low Speed Aggregate Surfaced Roads Are About Equal to Haul Costs Haul Cost = f(operating cost, load, speed) Haul Cost = f(operating cost, load, speed) = $0.25-0.30/ton-mile = $0.25-0.30/ton-mile Maintenance Cost = $.20-25/ton-mile Maintenance Cost = $.20-25/ton-mile
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Opportunities Reduce tire inflation pressure Recycle aggregate from temporary and decommissioned roads
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Lower Tire Inflation Pressure Road Impacts Less rock required Less rock required Lower road maintenance (fewer washboards and shallower ruts) Lower road maintenance (fewer washboards and shallower ruts) Vehicle Impacts Less truck maintenance (less shock) Less truck maintenance (less shock) Fewer flats (fewer punctures) Fewer flats (fewer punctures) Improved mileage (less tire slip) Improved mileage (less tire slip) Longer Hauling Season
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Aggregate Depth
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Recycling Aggregate Many forest roads are used intermittently. Why let rock sit not earning interest? Aggregate in many locations is expensive ($20,000-$30,000 per mile in Coast Range). Harvest Scheduling and Road Operations Problem
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Costs of Rock Recovery New Rock - $5-20+ per ton depending on source, quality and distance Pickup Existing Rock - $1-2 per ton + $1/ton processing + $ 0.4/ton- mile + $0.3/ton-mile road use fee
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Improve Truck Scheduling Reduce truck waiting times at landings and mills and mills 30+ minute waits not uncommon 30+ minute waits not uncommon Increase percent of loaded miles 40-45% not uncommon 40-45% not uncommon
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Summary Lots of opportunities for improved decision support : truck configurations load efficiency harvest and road operations truck scheduling
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